Thursday, April 24, 2014

For the second week in a row my Wednesday morning Green-Wood Cemetery tour was met with less than ideal spring migration weather. The skies were clear and beautiful, but north-west winds gusting to 35 mph made it feel more like early-March than late-April. Cold and wind aside, there were still some highlights to report.

At the risk of sounding repetitive, it was nice to see that the two Red-headed Woodpeckers are still hanging around the cemetery. Now in adult plumage, they are stunning to see compared to our more subtly marked resident woodpeckers. With the two birds at opposite sides of Green-Wood, I wonder if they have ever crossed paths. In addition, I am still unsure of their sex. Red-headed Woodpeckers are sexually monomorphic, that is, the outward appearance to the males and females are identical. I thought that their vocalizations might give me a clue, but learned that it is somewhat complex with this species. I found one online document prepared by Chicago Audubon for a Red-headed Woodpecker survey in which they explain:

"RHWO exhibits 3 structurally distinct vocalizations. For convenience, these are arbitrarily termed Vocals 1, 2 and 3. Vocal 1 is a discrete call while the others exhibit both discrete and graded characteristics. Vocal 2 is the most gradated with the extreme of gradation associated with agonistic circumstances. All of the vocalizations, with the exception of Vocal 3, are limited to the breeding season. All three vocalizations are used by males. Females do not exhibit Vocal 1. Both sexes employ Vocals 2 and 3. Once the territory is fully established and pair bonding is complete, acoustic activity declines, especially when incubation commences."

I didn't find this too helpful, but you can read the entire piece, "Brief Overview of Sexual Dimorphism, Monochromaticism and Acoustic Repertoire of the Red-headed Woodpecker", here.

Since my last visit to the cemetery the magnolias and cherry trees have really popped. For the first hour of the walk we didn't find too much bird activity, but the blossoms were a nice second prize. We finally came across a small mixed flock of songbirds on the steep, wooded Bluff Side Path above the Sylvan Water. In the trees above we counted Blue-headed Vireo, Blue-gray Gnatcatcher, Ruby-crowned Kinglet, Palm Warbler, Pine Warbler and Yellow-rumped Warbler. Descending the ridge to the lake we found a mixed flock of swallows braving the strong winds and skimming back and forth in the air above the Sylvan Water. Normally fairly active during the spring, the wooded hillside on the south side of the lake was pretty quiet. It wasn't until we ascended Oaken Bluff, towards Horace Greeley, that we stumbled on the second songbird flock of the morning. Seven Palm Warblers were foraging on the ground beneath a stand of conifers. A still bare dogwood tree just beyond the flock held another gnatcatcher and vireo. After a moment I spotted my first Black-and-white Warbler of the season. Normally, finding a black-and-white in Brooklyn on April 23rd is not a big deal, but spring migration so far has seemed a little slow. On past Green-Wood Cemetery trips around this date I've tallied between 5 and 8 different species of warbler. Maybe things will pick up a bit more this weekend.

To read about what birds are moving and migration forecasts, check out Cornell's BirdCast forecasts here.